Small-Molecule Probes Reveal Esterases With Persistent Activity in Dormant and Reactivating Mycobacterium Tuberculosis

ACS Infect Dis. 2016 Dec 9;2(12):936-944. doi: 10.1021/acsinfecdis.6b00135. Epub 2016 Oct 13.

Abstract

Mycobacterium tuberculosis (Mtb) is the deadliest bacterial pathogen in the world. An estimated one-third of humans harbor Mtb in a dormant state. These asymptomatic, latent infections impede tuberculosis eradication due to the long-term potential for reactivation. Dormant Mtb has reduced enzymatic activity, but hydrolases that remain active facilitate pathogen survival. We targeted Mtb esterases, a diverse set of enzymes in the serine hydrolase family, and studied their activities using both activity-based probes (ABPs) and fluorogenic esterase substrates. These small-molecule probes revealed functional esterases in active, dormant, and reactivating cultures. Using ABPs, we identified five esterases that remained active in dormant Mtb, including LipM (Rv2284), LipN (Rv2970c), CaeA (Rv2224c), Rv0183, and Rv1683. Three of these, CaeA, Rv0183, and Rv1683, were catalytically active in all three culture conditions. Fluorogenic probes additionally revealed LipH (Rv1399c), Culp1 (Rv1984c), and Rv3036c esterase activity in dormant and active cultures. Esterases with persistent activity are potential diagnostic biomarkers or therapeutic targets for Mtb-infected individuals with latent or active tuberculosis.

Keywords: Mycobacterium tuberculosis; chemical biology; esterase; fluorescent; proteomics.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Antitubercular Agents / chemistry
  • Antitubercular Agents / pharmacology*
  • Bacterial Proteins / antagonists & inhibitors*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Drug Evaluation, Preclinical
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Esterases / antagonists & inhibitors*
  • Esterases / genetics
  • Esterases / metabolism
  • Humans
  • Latent Tuberculosis / microbiology*
  • Mycobacterium tuberculosis / drug effects*
  • Mycobacterium tuberculosis / enzymology*
  • Mycobacterium tuberculosis / genetics
  • Tuberculosis / microbiology

Substances

  • Antitubercular Agents
  • Bacterial Proteins
  • Enzyme Inhibitors
  • Esterases